1. Technical Field
This invention relates in general to an improved data access and storage device and in particular to an improved filtration system for data access and storage devices. Still more particularly, the invention relates to an improved breather filter for low profile hard disk drives.
2. Description of the Prior Art
The breather filter in a hard disk drive (HDD) equalizes the pressure inside the HDD with the pressure outside the HDD while preventing particle contamination from entering the HDD. To date, prior art breather filters have been relatively simple structures. A particle filter is typically attached to a hole in the cover of the HDD with double-sided adhesive tape. However, due to higher recording density requirements for HDDs, there have been increased demands on breather filters to better protect corrosion-sensitive components. Such components include disks with a Co-system magnetic film and MR or GMR heads formed from Ni, Fe, Co, and Mn. In order to protect these components, breather filters must do more than filter dust from the ambient air that enters the HDD. For example, breather filters also must control air inflow, purify the air of organic or acid gases, reduce the relative humidity of the air, and perform highly efficient absorption of organic out gas within the HDD.
In the prior art, these additional demands are capable of being met by providing an adsorbent material (such as active carbon or a carbonate) for the purification of the outside air (organic gas and acid gas), a diffusing tube for restricting air inflow and controlling humidity, and an additional adsorbent material (active carbon), different from the first, for efficient absorption of organic out gas in the HDD.
Two configurations of conventional breather filters for HDDs are shown in FIGS. 5 and 6. Each filter has a top cover 51 has a hole 52, a plastic filter main body 53 with an internal diffusing tube 54, and a recess 55. An adsorbent material 56, such as active carbon, is located in recess 55. Each filter also has a plastic flow barrier 57 for dispersing gas being passed through the adsorbent material 56, a particle filter 58, such as a HEPA(copyright) filter, and an adhesive agent 59. In either example, the purification of the outside air by the adsorbent material 56, the inflow restriction on the outside air, and the reduction in the humidity change by the diffusing tube 54 can be effectively attained.
The difference between the two configurations of FIGS. 5 and 6, is that in FIG. 5 the area of contacted between the adsorbent material 56 and the HDD interior is small because there is the flow barrier 57. Therefore, the organic out gas in the HDD interior cannot be absorbed in a highly efficient manner. However, in FIG. 6, the organic out gas in the HDD interior can be absorbed at high efficiency by providing a different adsorbent material 56 than the one employed in the purification of the outside air. The additional adsorbent material 56 would be placed on the exterior of the flow barrier 57.
Thus, it is possible to achieve the previously defined additional demands with the conventional breather filters of FIGS. 5 and 6. However, the number and thickness of the components must increased to accommodate these requirements. Therefore, the original overall thickness of the breather filter, which was relatively thin because it was structurally simple, can no longer be maintained. In particular, it is difficult to design a low profile HDD (having a thickness of approximately one inch) with a high efficiency breather filter which is capable of achieving the additional requirements. Thus, an improved, low profile breather filter for HDDs is needed.
The present invention relates to a breather filter that is employed in a hard disk drive (HDD) by attaching it to a hole provided in the cover of the HDD. The breather filter is configured by preparing a first sheet forming a diffusing tube at a position corresponding to the hole provided in the cover of the HDD, a second sheet forming an opening at a position corresponding to the diffusing tube of the first sheet, a third sheet having an adsorbent layer at a position corresponding to the opening in the second sheet, a fourth sheet comprising a filter layer covering the adsorbent layer of the third sheet.
The breather filter is assembled by stacking the four sheets. This configuration forms a thin breather filter that can be mounted on a low profile HDD having a thickness of approximately one inch. The breather filter performs the same functions as conventional breather filters, such as air purification, inflow restriction, reduction in humidity change, and highly efficient absorption of organic out gas in the HDD interior, by forming the diffusing tube and the adsorbent layer in the respective sheets.
The four sheets are preferably retained with adhesive. For example, the first and third sheets may be assembled with double-sided adhesive tape. In addition, an adsorbent layer provided in the third sheet is equipped with an active carbon fiber containing a carbonate. Moreover, the adsorbent layer in the third sheet is capable of covering a portion or all of the opening formed in the second sheet. Accordingly, it is an object of the present invention to provide an improved data access and storage device.
It is an additional object of the present invention to provide an improved filtration system for data access and storage devices.
Still another object of the present invention is to provide an improved breather filter for low profile hard disk drives.
The foregoing and other objects and advantages of the present invention will be apparent to those skilled in the art, in view of the following detailed description of the preferred embodiment of the present invention, taken in conjunction with the appended claims and the accompanying drawings.